The most common and most likely answer to this crossword clue is the 6 letter word REPROS
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Buddy explains!
The straight part
We know that "High-quality proofs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case high-quality proofs = repros.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does REPROS mean?
REPROS noun- The proof prepared in offset printing, with all elements positioned on the page.
- The act of reproducing new individuals biologically.
- The act of making copies.
- A copy of something, as in a piece of art; a duplicate.
- The reproduction, reprinting and copying of graphics, especially using electromechanical or photographic methods